Our paper is organized as follows. In Section , we present a brief introduction of the SANS geometries of basic interest, notably conventional transmission SANS, near-surface SANS, and grazing-incidence SANS. This is followed, in Section , by an account of proof-of-concept measurements on the non-centrosymmetric cubic chiral magnet MnSi which exhibits a well-documented magnetic phase diagram [1]}. Our experimental results provide certainty that NS-SANS, with its modified scattering geometry compared to transmission SANS, provides a complete depiction of the nanoscale periodicities present within a magnetic sample. It showcases the applicability of NS-SANS for the study of nano-confined materials, which would otherwise possess insufficient scattering volumes to be measured in transmission. The experimental results motivate the prediction of the neutron scattering patterns arising from thin films of MnSi in Section , provided the same magnetically modulated phases would form as in bulk MnSi. Considering the Fourier transformation of the real-space magnetic configurations, we present a complete catalogue of scattering patterns arising from long-wavelength magnetic modulations for each orientation of the three-dimensional order with respect to the scattering plane. Our paper finishes in Section  with a brief account of the main conclusions.
